Machinist basic fitting :
- File flat :
Check the height of the bench vice .if the height is more. Use platform and if it less select and use another workbench.
Hold the job in the bench vice with a projection of 5 to 10 mm from the top of the vice jaw
Select flat files of various grades and length according to the
- Size of the jaw
- Quantity of metal to be removed
- Material of job.
Check whether the handle of the files fits tightly.
Hold the handle of the files and push the files forward using your right hand.
Hold the tip of the file according to the quantity of the metal to be removed.
* For heavy filling
* For light filling
* For removing local unevenness
Checking flatness and squareness
This shall help you to
* check flatness
* check squareness
#.check flatness:
Use the blade of the try square as a straight edge for checking flatness.
Place the blade of the try square on the surface on the surface to be checked in all directions as to cover the entire surface.
Do the checking facing the light. Light gap will indicate high and low spots.
#.check squareness:
Consider the large finished surface as the reference surface. Ensure that the reference surface is filled perfectly and is free from burrs.
This shall help you to
- Mark parallel lines using a jenny caliper.
- Set the jenny caliper to the size to be marked (dimension) with the help of a steel rule.
- Inclined slightly and move the jenny caliper with uniform speed and mark lines.
- Make, witness marks on the lines marked using a 60 percentage prick punch. The witness Mark should not be too close to one another.
Skill :
At the end of this exercise, you shall be able to. Draw lines on metallic surfaces by scribe'rs. Draw parallel lines on metallic surfaces by jenny caliper. Draw parallel lines with a surface gauge supporting the job against the angle plate. Draw angles with a simple protractor and scribe'r. Bisect the angles with a divider. Draw circles with a divider. Draw curves and tangents with dividers and scribe'rs. Register the profile by dot punching. Punch the center of the circle with a center punch and ball-peen hammer. Re-sharpen a blunt center punch/dot punch.
Knowledge :
At the end of these exercises, you shall be able to name the commonly used caliper.
- State the advantages of a spring joint caliper.
- State the purpose of a steel rule.
- State the precautions to be followed while using steel rules.
- Name the parts of a try square.
- State the uses of the try square.
- State the uses of the jenny caliper.
- Identify the parts of a divider.
- State the uses of the dividers.
- State the specifications of dividers.
- State some important hints on the divider point.
- State the uses of the surface gauges.
- State the constructional features of surface gauges.
- Name the different types of the surface gauges.
- State the advantages of universal surface gauges.
- State the features of scribe'rs.
- State the uses of scribe'rs.
- List the names of semi-precision angular measuring instruments.
- Differentiate between bevel and universal bevel gauges.
- State the features of bevel protectors.
- Above the mentioned points are very important of the machinist practical
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